1. Field of the Invention
The present invention relates to a controlling apparatus for a synchronous engagement type automatic transmission, and more particularly to a controlling apparatus for a synchronous engagement type automatic transmission with which gears in the synchronous engagement type transmission are shifted through positional control by a shift select actuator to thereby automate speed change.
2. Description of the Related Art
An example of a conventional controlling method for a synchronous engagement type automatic transmission is disclosed in Japanese Patent Application Laid-Open No. Sho 63-270252. In this conventional controlling method, a drive force of an engine is inputted into a synchronous engagement type automatic transmission by an ON/OFF operation of an electromagnetic clutch, a three-position hydraulic cylinder for selection is driven by the operational combination of a pair of hydraulic electromagnetic valves to select the speed gears, and a three-position hydraulic cylinder for shift is driven by the operational combination of a pair of hydraulic electromagnetic valves, thereby shifting the speed gear stages for changing speed.
Also, there is a synchronous engagement type automatic transmission in which, upon speed change, gear stages are shifted by two motors, i.e., a shift motor and a select motor instead of the operational combination of a pair of hydraulic electromagnetic valves.
However, in the case where the shift/select position is not in a neutral position when a key switch is turned on, the above-described conventional controlling method for the synchronous engagement type automatic transmission suffers that the vehicle starts forward or backward if the engine is started without taking preventive measures.
Also, in the conventional controlling method for the synchronous engagement type automatic transmission, in the case where the shift/select position is not in the neutral position upon the turn-on of the key switch after the battery has been turned off, there is a problem in that, if a learning operation is effected using that position as reference, the shift neutral position learning and the shift completion position learning could not be performed normally.
The present invention has been made to solve the above problem inherent in the prior art, and an object of the present invention is therefore to provide a controlling apparatus for a synchronous engagement type automatic transmission with which gears in a synchronous engagement type transmission are shifted through positional control by a shift/select actuator to thereby automate speed change, solving the problem of returning the gear to the neutral position when a key switch is turned on, and improving accuracy in shift neutral position learning and shift completion position learning upon the turn-on of the key switch after the battery has been turned off.
According to a first aspect of the present invention, there is provided a controlling apparatus for a synchronous engagement type automatic transmission that automatically shifts plural gear stages of a synchronous engagement type staged transmission, the controlling apparatus comprising: a shift/select actuator for shifting the gear stages; a first detecting means for detecting a shift position of the automatic transmission; a second detecting means for detecting a select position of the automatic transmission; a third detecting means for detecting an rpm of an engine; and a control means for controlling the shift/select actuator on the basis of detection outputs of the first to third detecting means, in which, if the shift position and the select position are not in the neutral position when a key switch is turned on, the shift/select actuator is controlled to return the shift position and the select position to the neutral position.
According to a second aspect of the invention, in the controlling apparatus for a synchronous engagement type automatic transmission of the first aspect of the invention, the neutral position return is performed before a shift neutral position learning and a shift completion position learning upon turn-on of the key switch after the battery has been removed.
According to a third aspect of the invention, in the controlling apparatus for a synchronous engagement type automatic transmission of the first aspect of the invention, the neutral position return is performed when the engine is stalled.
According to a fourth aspect of the present invention, there is provided a controlling apparatus for a synchronous engagement type automatic transmission that automatically shifts plural gear stages of a synchronous engagement type staged transmission, the controlling apparatus comprising: a shift/select actuator for shifting the gear stages; a first detecting means for detecting a shift position of the automatic transmission; a second detecting means for detecting a select position of the automatic transmission; and a control means for controlling the shift/select actuator on the basis of detection outputs of the first and second detecting means, in which the shift/select actuator is controlled to return the shift position and the select position to a neutral position while a key switch is turned off.